Yes, there as you stated in your last paragraph clearly a difference in animal life and human life. I think we have to think on what animal life provides to society and what human life provides to society. Sure animal life provides things to society that are purposeful, but compared to what human life provides it really does not compare. Other than the food aspect that the animals provide, human life provides so much more to the world. Even though we can also say humans are also what is going to eventually destroy the world, but honestly humans do provide more for the world than animal life does.
I also do not approve of human cannibalism. Even if I was trapped in a collapsed cave and there was no exit and it was me and two other people, I would not resort to cannibalism to survive. I suppose I would be the one who would get eaten.